There are many types and designs of roof ventilating louvers used in both residential and business construction. Ventilating louvers permit passage of air out of the attic area to avoid excessive build up of heat and moisture, while at the same time preventing, with varying degrees of success, entry of precipitation from the atmosphere and roof into the building.
Many ventilating louvers attempt to prevent snow on the roof from entering the louver and hence from dripping into the attic area by extending the louver substantially above the roof itself. Such louvers are unsightly, expensive, and most importantly do not solve the problem when there is a heavy accumulation of snow on the roof.
Many louvers are designed with a cover which overlaps the ventilation opening in the louver base, thus preventing rain from entering the louver. During periods of snow accumulation, air warmer than the atmosphere exits through the louver, thus melting a small area of snow around the louver and permitting continued function of the ventilating louver. However, due to the sloping roof, snow tends to accumulate especially against the roof-apex side of the louver. Snow melting on this side of the louver easily drips into the louver itself once melted by the warm air escaping from the attic or when melted by warmer atmospheric conditions. Once snow has accumulated on the roof, the drippage inside the louver may be continuous. As the snow on the roof-apex side of the louver melts and drips through the louver, more snow may slide down the roof into the same position against the louver, or else collect there due to various wind conditions.
Roof louvers should be designed so as to allow one to clear the ventilation opening and the covering screen in the event of clogging from leaves or other debris. Also, the condition of the screen itself should be inspected periodically for unusually large holes caused by age or animals. The screen prevents animals and debris from entering the attic area.
Having a ventilation opening protected from the elements and a screen covering permitting periodic inspection cause increased cost in manufacture of louvers attempting to meet these design specifications.
The present invention provides for a louver which projects only slightly from the roof as compared with most other louvers, while at the same time enhancing protection from precipitation drippage through the ventilation opening by providing a unique slope portion on both the base and cover of the louver on the roof-apex side of each. The slope portions on the base and cover fit together to form a substantially continuous surface on the high side of the louver when installed on a sloping roof. Snow accumulation above the louver is thus prevented from entering the louver and causing drippage.
The sloping portion of the louver lends itself to the use of pilot posts and pilot holes designed for simple and time saving installation of the cover onto the base, allowing the installer to easily guide the cover into position over the base after the latter has been fastened down. The pilot posts and pilot holes together act as a hinge to first mutually orient the cover and base and then permit lowering of the cover into assured inter-fitting orientation with the base.
The cover of the present invention is removably secured to the base, allowing cleaning of the louver and inspection of the screen. The present invention also coordinates the size and pattern of the screen mesh openings with the size and location of the screen posts and fastener posts on the base, thereby permitting assembly of the louver in a way which eliminates the necessity of additional preformed post holes in the screen. The screen is secured to the base by the screen posts themselves, thus eliminating additional fasteners. These design features reduce the cost of manufacture.
The use of the novel screen fastening means and the design features provided by the slope portion and pilot posts and the molding of all posts integrally with the part to which it is permanently secured allow the base and cover to be inexpensively manufactured of molded plastic material, further reducing cost and improving appearance.